As a result of tolerances necessarily existing in the manufacture of automobile bodies, there often exists problems, of an essentially aesthetic nature, relating to an incorrect surface alignment between the closure lens of the headlight and the adjacent edges of the body. In fact, a headlight is fixed in the majority of cases not directly on the edges of the body, but to a support specially arranged inside this.
A known, but inconvenient, solution to this problem consists in placing on the screws assuring the fixing of the headlight on the body a series of spacing washers or the like of which the number is determined to assure the correct relative position between the lens and the body. However, such an adjustment procedure is extremely tedious, because the operator must time and again carry out the mounting and dismounting of the headlight, to determine by successive approaches the ideal number of washers to provide on each screw.